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Interest for Matched Sets of FQA12P20 / FQA19N20C for F5 Power Amp ?

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EUVL

EUVL

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Joined 2003
xen-audio.com
#1
Exactly 5 years ago, we bought some FQA12P20 / FQA19N20C in a GB for our F5 test build :
http://www.diyaudio.com/forums/group-buys/122074-eu-mini-group-buy-fqa19n20c-fqa12p20.html

They were from Digikey and are still in original Fairchild tubes.

Since then it is well known that we have changed over to the F5X and Toshiba power devices.
We still have 30+ pairs (single point Vgs prematched) left with no use in sight.
So we are happy to let them go to single ended F5 builders who do not like Toshiba's, for whatever reason.

They will be offered as NN / PP matched quads, xen-audio curve tracer matched for both Vgs (<<10mV, normally <5mV)
and Yfs (<<10%, normally < 5%), at 24V 0.3~2.5A, at 65°C case temperature.
This represents the exact working conditions of the FETs in a standard F5.

Each subscribers limited to one set (4 FETs NN-PP) per person, unless under-subscribed.
Price depends on curve tracer matching yield, but tentatively 250~300 HKD a set, all inclusive.
(Paypal charges, registered post world wide, etc.)
We do not cover postage losses, as usual.
Delivery some time July 2013, since matching schedule is totally full till then.

Any interest ?


Patrick
 
#2
Note that as published in the original F5 thread before, the Fairchild are not complementary devices.
i.e. both the Vgs & Yfs of the N devices differs significantly from the P devices at bias.
As such there is no N-P match possible, by the natural of the FETs.

So the above matching applies to match between devices of the same type.
Hope this is clear to all.


Patrick
 
#3
Here the Id vs Vgs curves at room temperature.
Red is N-FET, blue is P-FET.


Patrick
 

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  • FQA 12P20 19N20C.png
    FQA 12P20 19N20C.png
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#6
Hi Patrick,

As I have a dual output version of the F5, I would be interested in a matched octet of devices matched between types(N-N-N-N and P-P-P-P) if possible. If there is a lot of demand for the devices, I'm sure I could cope with just a quad set🙂.

Thanks
Cornelius
 
#12
billyk USA 1 set.
vawykca Europe 1[+1] set [quad is possible].
emyeuoi Asia 1[+1] set
scalpel South Africa 1[+1] set
Franzm Europe 1[+1] set

1[+1] set = 2 sets if under-subscribed.
Otherwise one set per person, so that others also have a chance.
My estimate is about 12~14 sets of NN-PP.


Patrick
 
#15
billyk USA 1 set [+1] set quad if doable
vawykca Europe 1[+1] set [quad is possible].
emyeuoi Asia 1[+1] set
scalpel South Africa 1[+1] set
Franzm Europe 1[+1] set
Earthquake 1+ [+1] set
tome 1+ [+1] set

I added the second set for myself, looking to build a V2, but very happy to receive what is available!
 
#17
billyk USA 1 set
vawykca Europe 1[+1] set [quad is possible].
emyeuoi Asia 1[+1] set
scalpel South Africa 1[+1] set
Franzm Europe 1[+1] set
Earthquake (???) 1[+1] set
tome Europe 1[+1] set
Jallhalla Europe 1 set


Since we are over 14 sets already, I shall start taking off optional sets (last subscriber for optional set to go first), should there be any new more subscribers.
So from now on only 1 quad set per person please.

Sorry billyk ......
I am sure you understand.
(It is actually less work for us to sell 2 sets each to 7 subscribers.)


Thanks,
Patrick
 
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